Adenosine-stress cardiac magnetic resonance imaging in suspected coronary artery disease: a net cost analysis and reimbursement implications

Health Economic Analysis of CMR: A Systematic Review

INTRODUCTION

Uptake of cardiac magnetic resonance (CMR) in Australia has been limited by issues of cost and access. There is a need to inform future application of CMR by evaluating pertinent health economic literature. We sought to perform a systematic review on the health economic data as it pertains to CMR.

METHODS

Eight databases (biomedical/health economic) were searched for relevant articles highlighting economic evaluations of CMR. Following screening, studies that reported health economic outcomes (e.g., dollars saved, quality adjusted life years [QALY] and cost effectiveness ratios) were included. Data on cost effectiveness, clinical/disease characteristics, type of modelling were extracted and summarised.

RESULTS

Thirty-eight (38) articles informed the systematic review. Health economic models used to determine cost effectiveness included both trial-based studies (n=14) and Markov modelling (n=24). Comparative strategies ranged from nuclear imaging, stress echocardiography and invasive angiography. The disease states examined included coronary artery disease (23/38), acute coronary syndrome (3/38), heart failure (5/38) and miscellaneous (7/38). The majority of studies (n=29/38) demonstrated CMR as a strategy which is either economically dominant, cost-effective or cost-saving.

CONCLUSION

This systematic review demonstrates that CMR is cost-effective depending on diagnostic strategy, population and disease state. The lack of standardised protocols for application of CMR, economic models used and outcomes reported limits the ability to meta-analyse the available health economic data.

The Role and Advantages of Cardiac Magnetic Resonance in the Diagnosis of Myocardial Ischemia

Ischemic heart disease continues to be the leading cause of death and disability worldwide. For the diagnosis of ischemic heart disease, some form of cardiac stress test involving exercise or pharmacological stimulation continues to play an important role, despite advances within modalities like computer tomography for the noninvasive detection and characterization of epicardial coronary lesions. Among noninvasive stress imaging tests, cardiac magnetic resonance (CMR) combines several capabilities that are highly relevant for the diagnosis of ischemic heart disease: assessment of wall motion abnormalities, myocardial perfusion imaging, and depiction of replacement and interstitial fibrosis markers by late gadolinium enhancement techniques and T1 mapping. On top of these qualities, CMR is also well tolerated and safe in most clinical scenarios, including in the presence of cardiovascular implantable devices, while in the presence of renal disease, gadolinium-based contrast should only be used according to guidelines. CMR also offers outstanding viability assessment and prognostication of cardiovascular events. The last 2019 European Society of Cardiology guidelines for chronic coronary syndromes has positioned stress CMR as a class I noninvasive imaging technique for the diagnosis of coronary artery disease in symptomatic patients. In the present review, we present the current state-of-the-art assessment of myocardial ischemia by stress perfusion CMR, highlighting its advantages and current shortcomings. We discuss the safety, clinical, and cost-effectiveness aspects of gadolinium-based CMR-perfusion imaging for ischemic heart disease assessment.

The Merits, Limitations, and Future Directions of Cost-Effectiveness Analysis in Cardiac MRI with a Focus on Coronary Artery Disease: A Literature Review

Cardiac magnetic resonance (CMR) imaging has a wide range of clinical applications with a high degree of accuracy for many myocardial pathologies. Recent literature has shown great utility of CMR in diagnosing many diseases, often changing the course of treatment. Despite this, it is often underutilized possibly due to perceived costs, limiting patient factors and comfort, and longer examination periods compared to other imaging modalities. In this regard, we conducted a literature review using keywords “Cost-Effectiveness” and “Cardiac MRI” and selected articles from the PubMed MEDLINE database that met our inclusion and exclusion criteria to examine the cost-effectiveness of CMR. Our search result yielded 17 articles included in our review. We found that CMR can be cost-effective in quality-adjusted life years (QALYs) in select patient populations with various cardiac pathologies. Specifically, the use of CMR in coronary artery disease (CAD) patients with a pretest probability below a certain threshold may be more cost-effective compared to patients with a higher pretest probability, although its use can be limited based on geographic location, professional society guidelines, and differing reimbursement patterns. In addition, a stepwise combination of different imaging modalities, with conjunction of AHA/ACC guidelines can further enhance the cost-effectiveness of CMR.

The Potential of Oxygenation-Sensitive CMR in Heart Failure

PURPOSE OF REVIEW

Cardiac magnetic resonance imaging (CMR) use in the context of heart failure (HF) has increased over the last decade as it is able to provide detailed, quantitative information on function, morphology, and myocardial tissue composition. Furthermore, oxygenation-sensitive CMR (OS-CMR) has emerged as a CMR imaging method capable of monitoring changes of myocardial oxygenation without the use of exogenous contrast agents.

RECENT FINDINGS

The contributions of OS-CMR to the investigation of patients with HF includes not only a fully quantitative assessment of cardiac morphology, function, and tissue characteristics, but also high-resolution information on both endothelium-dependent and endothelium-independent vascular function as assessed through changes of myocardial oxygenation. In patients with heart failure, OS-CMR can provide deep phenotyping on the status and important associated pathophysiology as a one-stop, needle-free diagnostic imaging test.

Influence of contrast agent and spatial resolution on myocardial strain results using feature tracking MRI

OBJECTIVES

Feature tracking for assessing myocardial strain from cardiac magnetic resonance (CMR) cine images detects myocardial deformation abnormalities with prognostic implication, e.g., in myocardial infarction and cardiomyopathy. Standards for image acquisition and processing are not yet available. Study aim was analyzing the influence of spatial resolution and contrast agent on myocardial strain results.

METHODS

Seventy-five patients underwent CMR for analyzing peak systolic circumferential, longitudinal, and radial strain. Group A included n = 50 with normal left ventricular ejection fraction, no wall motion abnormality, and no fibrosis on late enhancement imaging. Group B included n = 25 with chronic myocardial infarct. For feature tracking, steady-state free precession cine images were acquired repeatedly. (1) Native standard cine (spatial resolution 1.4 × 1.4 × 8 mm³). (2) Native cine with lower spatial resolution (2.0 × 2.0 × 8 mm³). (3) Cine equal to variant 1 acquired after administration of gadoteracid.

RESULTS

Lower spatial resolution was associated with elevated longitudinal strain (- 21.7% vs. - 19.8%; p < 0.001) in viable myocardium in group A, and with elevated longitudinal (- 17.0% vs. - 14.3%; p = 0.001), circumferential (- 18.6% vs. - 14.6%; p = 0.002), and radial strain (36.8% vs. 31.0%; p = 0.013) in infarcted myocardium in group B. Gadolinium administration was associated with reduced circumferential (- 21.4% vs. - 22.3%; p = 0.001) and radial strain (44.4% vs. 46.9%; p = 0.016) in group A, whereas strain results of the infarcted tissue in group B did not change after contrast agent administration.

CONCLUSIONS

Variations in spatial resolution and the administration of contrast agent may influence myocardial strain results in viable and partly in infarcted myocardium. Standardized image acquisition seems important for CMR feature tracking.

KEY POINTS

• Feature tracking is used for calculating myocardial strain from cardiac magnetic resonance (CMR) cine images. • This prospective study demonstrated that CMR strain results may be influenced by spatial resolution and by the administration of gadolinium-based contrast agent. • The results underline the need for standardized image acquisition for CMR strain analysis, with constant imaging parameters and without contrast agent.

Additive value of 3T cardiovascular magnetic resonance coronary angiography for detecting coronary artery disease

BACKGROUND

The purpose of the work was to evaluate the incremental diagnostic value of free-breathing, contrast-enhanced, whole-heart, 3 T cardiovascular magnetic resonance coronary angiography (CE-MRCA) to stress/rest myocardial perfusion imaging (MPI) and late gadolinium enhancement (LGE) imaging for detecting coronary artery disease (CAD).

METHODS

Fifty-one patients with suspected CAD underwent a comprehensive cardiovascular magnetic resonance (CMR) examination (CE-MRCA, MPI, and LGE). The additive diagnostic value of MRCA to MPI and LGE was evaluated using invasive x-ray coronary angiography (XA) as the standard for defining functionally significant CAD (≥ 50% stenosis in vessels > 2 mm in diameter).

RESULTS

90.2% (46/51) patients (54.0 ± 11.5 years; 71.7% men) completed CE-MRCA successfully. On per-patient basis, compared to MPI/LGE alone or MPI alone, the addition of MRCA resulted in higher sensitivity (100% vs. 76.5%, p < 0.01), no change in specificity (58.3% vs. 66.7%, p = 0.6), and higher accuracy (89.1% vs 73.9%, p < 0.01) for CAD detection (prevalence = 73.9%). Compared to LGE alone, the addition of CE-MRCA resulted in higher sensitivity (97.1% vs. 41.2%, p < 0.01), inferior specificity (83.3% vs. 91.7%, p = 0.02), and higher diagnostic accuracy (93.5% vs. 54.3%, p < 0.01).

CONCLUSION

The inclusion of successful free-breathing, whole-heart, 3 T CE-MRCA significantly improved the sensitivity and diagnostic accuracy as compared to MPI and LGE alone for CAD detection.

Effect of Nitroglycerin on the Performance of MR Coronary Angiography

PURPOSE

To systematically investigate the effect of sublingual glyceryl trinitrate (nitroglycerin=nitro=glyceryl trinitrate=GTN=C₃ H₅ N₃ O₉ [NTG]) on the diagnostic performance of MR coronary artery imaging (MRCA) to detect relevant coronary artery disease (CAD).

MATERIALS AND METHODS

Thirty-five healthy volunteers and 25 patients with suspected or proven CAD (all in sinus rhythm) underwent MRCA before and after NTG using a contrast-agent free, three-dimensional, navigator-based, steady state free precession acquisition (voxel size 1.0 × 0.7 × 0.7 mm³ ) at 1.5 Tesla. Target parameters were stenosis detection (>50%), visible vessel length (straightened planar reconstruction) and vessel diameter (curved planar reconstruction, measured proximal/medial/distal). In patients, invasive coronary angiography served as reference.

RESULTS

NTG led to increase of the coronary diameter both in healthy volunteers (right coronary artery [RCA]: 3.2 to 3.7 mm, P < 0.001; left anterior descending coronary artery [LAD]: 2.9 to 3.4 mm, P = 0.009; left circumflex coronary artery [LCx]: 2.8 to 3.3 mm, P < 0.001) and patients (RCA 3.5 to 4.0 mm, P = 0.01; LAD 3.3 to 3.7 mm, P = 0.008; LCx: 2.9 to 3.3 mm, P = 0.03). Visible vessel length increased after NTG for the LAD (volunteers: 72 to 84 mm, P = 0.03; patients: 56 to 78 mm, P = 0.01) and for LCx (volunteers: 48 to 60 mm, P = 0.02). Sensitivity to detect > 50% stenosis improved after NTG from 88.0 to 96%, specificity from 46.5 to 69.8%, diagnostic accuracy from 61.8 to 79.4% and positive/negative predictive value from 48.9 to 64.9% and 87.0 to 96.8%, respectively.

CONCLUSION

Sublingual administration of NTG significantly enhanced the visibility of the coronary arteries and improved the detection of coronary artery stenosis.

LEVEL OF EVIDENCE

2 J. MAGN. RESON. IMAGING 2017;45:1419-1428.

Role of cardiovascular magnetic resonance in the guidelines of the European Society of Cardiology

BACKGROUND

Despite common enthusiasm for cardiovascular magnetic resonance (CMR), its application in Europe is quite diverse. Restrictions are attributed to a number of factors, like limited access, deficits in training, and incomplete reimbursement. Aim of this study is to perform a systematic summary of the representation of CMR in the guidelines of the European Society of Cardiology (ESC).

METHODS

Twenty-nine ESC guidelines were screened for the terms "magnetic", "MRI", "CMR", "MR" and "imaging". As 3 topics were published twice (endocarditis, pulmonary hypertension, NSTEMI), 26 guidelines were finally included. MRI in the context of non-cardiovascular examinations was not recognized. The main CMR-related conclusions and, if available, the level of evidence and the class of recommendation were extracted.

RESULTS

Fourteen of the 26 guidelines (53.8%) contain specific recommendations regarding the use of CMR. Nine guidelines (34.6%) mention CMR in the text, and 3 (11.5%) do not mention CMR. The 14 guidelines with recommendations regarding the use of CMR contain 39 class-I recommendations, 12 class-IIa recommendations, 10 class-IIb recommendations and 2 class-III recommendations. Most of the recommendations have evidence level C (41/63; 65.1%), followed by level B (16/63; 25.4%) and level A (6/63; 9.5%). The four guidelines, which absolutely contained most recommendations for CMR, were stable coronary artery disease (n = 14), aortic diseases (n = 9), HCM (n = 7) and myocardial revascularization (n = 7).

CONCLUSIONS

CMR is represented in the majority of the ESC guidelines. They contain many recommendations in favour of the use of CMR in specific scenarios. Issues regarding access, training and reimbursement have to be solved to offer CMR to patients in accordance with the ESC guidelines.

Incremental cost-effectiveness of dobutamine stress cardiac magnetic resonance imaging in patients at intermediate risk for coronary artery disease

Aims

The effectiveness of stress cardiac magnetic resonance (CMR) as a gatekeeper for coronary angiography (CA) has been established. Level five HTA studies according to the hierarchical model of diagnostic test evaluation are not available.

Methods

This cohort study included 1,158 consecutive patients (mean age 63 ± 11 years, 42 % women) presenting at our institution between January 1, 2003 and December 31, 2004 with suspected coronary artery disease (CAD) for an elective CA. The patients were assessed for eligibility and propensity score matching was applied to address selection bias regarding the patients’ allocation to CMR or direct CA. Median patient follow-up was 7.9 years (95 % CI 7.8–8.0 years). The primary effect was calculated as relative survival difference. The cost unit calculation (per patient) at our institute was the source of costs.

Results

Survival was similar in CMR and CA (p = 0.139). Catheterizations ruling out CAD were significantly reduced by the CMR gate-keeper strategy. Patients with prior CMR had significantly lower costs at the initial hospital stay and at follow-up (CMR vs. CA, initial: 2,904€ vs. 3,421€, p = 0.018; follow-up: 2,045€ vs. 3,318€, p = 0.037). CMR was cost-effective in terms of a contribution of 12,466€ per life year to cover a part of the CMR costs.

Conclusion

Stress CMR prior to CA was saving 12,466€ of hospital costs per life year. Lower costs at follow-up suggest sustained cost-effectiveness of the CMR-guided strategy.

Electronic supplementary material

The online version of this article (doi:10.1007/s00392-014-0793-0) contains supplementary material, which is available to authorized users.

Cardiac magnetic resonance imaging for ischemic heart disease: update on diagnosis and prognosis

Despite significant advancements in the treatment of ischemic heart disease (IHD), IHD remains a leading cause of mortality and morbidity. In addition, there remains clinical equipoise regarding a number of important management issues across the spectrum of IHD, from evaluating patients with chest pain in the emergency department, to deciding whether patients with chronic stable angina or severe ischemic cardiomyopathies should undergo invasive revascularization procedures. Recent data over the past 2 decades has demonstrated that cardiac magnetic resonance imaging is highly accurate and carries robust prognostic value in the evaluation of patients with both acute and chronic IHD. The combination of cine imaging for cardiac structure and function, late gadolinium enhancement imaging of myocardial scar, qualitative and quantitative measures of myocardial fibrosis, and stress perfusion imaging for the presence and extent of ischemia provides a comprehensive and detailed characterization of cardiac anatomy and physiology that guides critical treatment decisions for patients. This review aims to cover both the diagnostic and prognostic utility of cardiac magnetic resonance imaging for the spectrum of IHD.

Diagnostic performance of non-contrast-enhanced whole-heart magnetic resonance coronary angiography in combination with adenosine stress perfusion cardiac magnetic resonance imaging

BACKGROUND

We sought to evaluate the diagnostic performance of 1.5-T non-contrast enhanced whole-heart magnetic resonance coronary angiography (MRCA) alone and in combination with adenosine stress cardiac magnetic resonance imaging (CMR-Perf). MRCA has been proposed to allow for detection of coronary artery disease (CAD). Yet, recent studies failed to show an incremental value of MRCA when added to CMR-Perf.

METHODS

Non-Gadolinium 1.5-T contrast-enhanced, electrocardiogram-triggered, navigator-gated free-breathing MRCA was performed in 144 patients (pts) with suspected or known CAD. Accuracy of MRCA in detecting CAD was evaluated using X-ray coronary angiography as the reference. A novel algorithm was used to combine the results of MRCA and CMR-Perf.

RESULTS

MRCA was diagnostic in 96/144 pts (67%) with regular breathing (mean age 62.5 ± 13); 77% of all coronary segments (939/1226) and 92% of segments suitable for percutaneous coronary intervention (792/866) were assessable. In 59 pts a novel algorithm to combine MRCA and CMR-Perf was performed with high diagnostic performance: accuracy, sensitivity, specificity, negative and positive predictive values were 91.5% (54/59; 95% CI, 84%-99%), 95.7% (22/23; 77-100), 88.9% (32/36; 74-96), 84.6% (22/26; 71-99), and 97.0% (32/33; 91-100). Compared to the combined use of CMR-Perf and late gadolinium enhancement, specificity with the novel algorithm significantly increased (P = .008).

CONCLUSION

MRCA has a high assessability in segments suitable for percutaneous coronary intervention in pts with regular breathing. The combined use of MRCA and CMR-Perf improved specificity for the detection of significant CAD.

Cost-effectiveness analysis for imaging techniques with a focus on cardiovascular magnetic resonance

With the need for healthcare cost-containment, increased scrutiny will be placed on new medical therapeutic or diagnostic technologies. Several challenges exist for a new diagnostic test to demonstrate cost-effectiveness. New diagnostic tests differ from therapeutic procedures due to the fact that diagnostic tests do not generally directly affect long-term patient outcomes. Instead, the results of diagnostic tests can influence management decisions for patients and by this route, diagnostic tests indirectly affect long-term outcomes. The benefits from a specific diagnostic technology depend therefore not only on its performance characteristics, but also on other factors such as prevalence of disease, and effectiveness of existing treatments for the disease of interest. We review the concepts and theories of cost-effectiveness analyses (CEA) as they apply to diagnostic tests in general. The limitations of CEA across different study designs and geographic regions are discussed, and we also examine the strengths and weakness of the existing publications where CMR was the focus of CEA compared to other diagnostic options.

Impact of cardiac magnetic resonance imaging on cardiac device and surgical therapy: a prospective study

Cardiac magnetic resonance (CMR) imaging may allow more appropriate selection of patients for cardiac device implantation and/or cardiac surgery. In this prospective observational study we evaluated the impact of CMR imaging on cardiac device and surgical therapy. All CMR examinations performed in a single centre over a 2 year period were prospectively recorded in a dedicated database under 4 clinical pathways [cardiomyopathy, viability, tumour/mass and arrythmogenic right ventricular cardiomyopathy (ARVC)]. Baseline data entered included planned cardiac device implantation and/or cardiac surgical intervention. Patients were contacted 6 months following CMR to evaluate the impact of CMR on planned therapy. Cost savings due to CMR were calculated as the number of surgical or device procedures averted following CMR scanning multiplied by their respective cost weights. Of 732 CMR examinations performed, the clinical pathway was cardiomyopathy in 488 (67 %), ARVC in 118 (16 %), viability in 92 (12 %) and tumour/mass in 34 (5 %). Six month follow-up was available in 666/732 patients. Following CMR, 56/150 (37 %) of patients with an initial plan for device implantation or cardiac surgery, did not undergo the planned intervention (P < 0.001, one-sample exact binomial test). Of 516 patients without an initial device or surgical plan, 33 (6 %) CMR resulted in device implantation or cardiac surgery (P < 0.001, Chi squared). Overall, the estimated saving due to CMR-guided management changes was AUD$737,270. CMR has a significant impact on patient management and offers potential cost savings with respect to selection of device and surgical therapy for cardiac disease.

Adenosine stress cardiovascular magnetic resonance-observation unit management of patients at intermediate risk for acute coronary syndrome: a possible strategy for reducing healthcare-related costs

OPINION STATEMENT

Although clear algorithms for diagnosis and treatment of patients with chest pain at low or high risk for an acute coronary syndrome (ACS) exist, they are less well delineated for patients presenting with chest pain with an intermediate risk for ACS. In patients presenting acutely or subacutely to emergency departments (EDs) at high risk for ACS, such as those with ST segment elevation on their 12-lead electrocardiogram (ECG), immediate contrast coronary angiography is performed. On the other hand, chest pain observation units (OUs) are recommended for managing those with chest pain at low risk for an ACS event. In this setting, these OUs are associated with lower healthcare resource utilization and improved cost-effectiveness. Cost-effective diagnosis and treatment options are important goals in healthcare delivery systems. The presentation of patients at intermediate risk for ACS represents an emerging source of resource utilization for EDs. These patients often exhibit pre-existing coronary artery disease, may have sustained prior myocardial infarction, and exhibit multiple comorbidities such as diabetes and hypercholesterolemia. Importantly, however, they will not have evidence of ST elevation on their 12-lead ECG nor will they exhibit serum markers (troponin or creatinine kinase elevations) indicative of ACS. As a consequence of existing co-morbidities, their management becomes time-consuming and may require inpatient monitoring, observation, and cardiac stress testing. Cardiovascular magnetic resonance (CMR) is a powerful tool for risk stratification and prognosis determination in patients in need of stress testing at intermediate risk of ACS. For those who present with acute chest pain syndromes, the combination of CMR in an OU setting represents a potentially attractive option for reducing healthcare-related expenditures without compromising patient outcomes. Recent study results from single centers suggest that CMR-OU care may result in fewer unnecessary hospital admissions and invasive procedures in those presenting with intermediate risk ACS. Further research utilizing stress CMR testing from multiple centers in OU settings is needed to determine if this model of care improves efficiency, reduces healthcare costs, and delivers optimum care in individuals presenting to EDs with chest pain at intermediate risk of ACS.

Cost evaluation of cardiovascular magnetic resonance versus coronary angiography for the diagnostic work-up of coronary artery disease: application of the European Cardiovascular Magnetic Resonance registry data to the German, United Kingdom, Swiss, and United States health care systems

BACKGROUND

Cardiovascular magnetic resonance (CMR) has favorable characteristics for diagnostic evaluation and risk stratification of patients with known or suspected CAD. CMR utilization in CAD detection is growing fast. However, data on its cost-effectiveness are scarce. The goal of this study is to compare the costs of two strategies for detection of significant coronary artery stenoses in patients with suspected coronary artery disease (CAD): 1) Performing CMR first to assess myocardial ischemia and/or infarct scar before referring positive patients (defined as presence of ischemia and/or infarct scar to coronary angiography (CXA) versus 2) a hypothetical CXA performed in all patients as a single test to detect CAD.

METHODS

A subgroup of the European CMR pilot registry was used including 2,717 consecutive patients who underwent stress-CMR. From these patients, 21% were positive for CAD (ischemia and/or infarct scar), 73% negative, and 6% uncertain and underwent additional testing. The diagnostic costs were evaluated using invoicing costs of each test performed. Costs analysis was performed from a health care payer perspective in German, United Kingdom, Swiss, and United States health care settings.

RESULTS

In the public sectors of the German, United Kingdom, and Swiss health care systems, cost savings from the CMR-driven strategy were 50%, 25% and 23%, respectively, versus outpatient CXA. If CXA was carried out as an inpatient procedure, cost savings were 46%, 50% and 48%, respectively. In the United States context, cost savings were 51% when compared with inpatient CXA, but higher for CMR by 8% versus outpatient CXA.

CONCLUSION

This analysis suggests that from an economic perspective, the use of CMR should be encouraged as a management option for patients with suspected CAD.

Influence of small caliber coronary arteries on the diagnostic accuracy of adenosine stress cardiac magnetic resonance imaging

Background and aims

Positive predictive value (PPV) of adenosine stress cardiac magnetic resonance (CMR) for coronary artery disease (CAD) is unsatisfactory. We investigated the impact of coronary caliber variability on this limitation in CMR performance.

Methods and results

206 consecutive patients with myocardial ischemia during CMR and subsequent coronary angiography (CA) were studied. Patients were examined in a 1.5-T scanner. After adenosine infusion, myocardial first-pass sequence using gadolinium-based contrast agent was performed and compared with rest perfusion. CAD was invasively confirmed in 165 [true positive (TP); PPV, 80.1%] and ruled out in 41 patients [false positive (FP)]. TP and FP were comparable for pre-test risk and CMR findings. We found a significant association between FP CMR and the presence of a small caliber coronary vessel (proximal diameter < one standard deviation below the mean) supplying the area of ischemia (chi-square 42.6, p < 0.0001). A small caliber artery ipsilateral to the ischemic region was a predictive parameter for FP versus TP discrimination (ROC area, 0.84 ± 0.04 vs. 0.59 ± 0.05; p < 0.0001). Further increment in diagnostic accuracy was achieved by including proximal ipsilateral/contralateral coronary diameter ratios (ROC area, 0.90 ± 0.03; p < 0.03).

Conclusions

Small caliber coronary arteries found as normal variations in right-dominant or left-dominant circulation may account for hypoperfusion in the absence of coronary stenosis and thus may cause FP adenosine stress CMR results. Non-invasive assessment of proximal coronary diameters in the vessel supplying the area of ischemia could reduce FP rates, raise the diagnostic accuracy of CMR for CAD and minimize subsequent superfluous CA.